Improvement in drafting-scales



. 'PATENTBD FEB. v l1865.

J. LYMAN.

DRAFTVING SCALE.

MNN.

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v UNITED .STATI-3stv 'l PATENT OFFICE.

' JosIAH LYMAN, or LENOX,' MASSACHUSETTS.

lmpsovEMENT IN DR'AFTING-SCALES'- Specification forming part of Letters vPatent No. 46.256, dated February 7, 1865.

To all ,wh/0m) it may concern:

' Be it knownA that I, J osrAH LYMAN, of Lenox, in the county of Berkshire, in the State of Massachusetts, have invented anew and Improved Drafting-Scale, valuable for all pur- ,poses of rectilinear drafting; and I do hereby declare'thatthe following is a full and exactdescription' thcreof,'reference being had to the accompanying drawings, and to the letters of 'reference marked-thereon, makinga part of this specification, in'wh' -hf'- Figure lis a planl View of the scale with its slide-spring and' attachment thereby to4 the'4 arm of the tri gonometeror T-square T Sq. Fi g. 2 is a longitudinal section of the instrument through-its center. AFigL3 is a transverse section through-the Vernier-piece, Vernierspring, and stop-screw St. s Fig. 4 is a plan view-@theslide-spring when applied to a triangular'scale, Tr Sc.' Fig. 5 is a transverse sectionof the lip-piece L, with the wire spring. v

To enab'e others'skilled in the art to make anduse myinventionylwill proceed 'to de-f vscribe its construction and operation.

The invention consists of three parts-viz., the scale proper with its two beveled edges, the verniers with their springs, and the slidespring.

num, or .of any similar metal; 'When' made plain-'that is, without verniers-the mostconvenient dimensions -are about one-twentieth two lon gitudin aledgcs beveled to such an angle and with4 the subdivisions so graduated upon them that each ofthe marks will guide with cer- 'taint'y the point ofthe needle or prick (While held in an upright position,- being traced by it y quite downtol the paper) in making a dot at the end of any required distance. 'lhe best to veii"ectthis object', L have found by experiment that an. angle forthe beveled edges-of about thirty zdegreeswvith a perpendicular. is required, and that the graduating-tool shall be lo shaped'as smoothlyr to cut out a deep, nar- )w chip entirely across in marking the edges,

v The scale may be used either with o r without4 theotherparts, or-with either of them separat'ely, as occasion may require. It may be madeof German silver, of steehof brass, of alumi- `This angle. of bevel is seen in thetransverse section, Fig.'3. The same angle exists in the destroyed. "Ivory agn`dbox-woil-sc'alcs with =inclined bordersl are ,comjlnom'but' not so inclined or so graduated on the edges' as to'guide are the subdivisions on a separate'level, as in 'of this arrangement of the' subdivisions is evi- .dent from thefact that the marks are univertional portions of a space. For when'the scale :is plain, in laying down any given distance,

one at the other end-of the required dist-ance,` being subdividedl by the eye"into-ten'equal parts-that-is, into hundredths of the vunitgiven dot and the terminal mark, 'while the needle is carried to the mark design-ating the required unit and tenth, and iu it a second-'dot 'is made.l On the other hand,I infmeasuringthe v distance `between anytwo points, either the .zcre-markar the other terminal mark is first read on the scale at this-or the other point.

When the scale is made-with' verniers its twelve and three-fourths inches, the dimensions in other respects heilig the same aS when made plain. v

V, Fig.1, shows the form and arrange-- v ment ofthe Vernier-pieces. V sp, at 'the -lett -end of the gure, isthe Vernier-spring, parbut forithe sake of distinctness left oii'at the other. 0'0 are orifices for the rivets. The Vernier-'pieces are fitted into slots' in the ends of the scale, held from ibeing elevated above its upper surface by the edges being pressed below its lower surface bythe'spring's, (as V sp' at the left end.) They are riveted to fthe Vernier-pieces bythe rivets lt R', Figs. 1, 2, and tbethumb-rivets T R T lt. "The thickness of lthe springs, which are made of brass .common equilateral triangular scale; but"V lwhen made of lwood tlleidii-'ision-marks cant'hey'would- -thus in ya lshort' time be torn' and at all the needle-point in makin ga dot. Nor

'the scale `herein described. "The great utility p sal guides for both entire spaces amlfor fraceither'the lspacenert to the zero-mark or the ythe-scale is slid'joh the paper till the required vportion offa space is embraced betwcenthe.

brought to-coincidev with one ofthem, While the units, tenths, and hundredths are instantly-g entire length, with these included, is about tially covering the 'Vernier-piece at that end,

beveled, as shown inFig. 3,' and from beingdeor German silver, is seen in Figs. 2 and 3and ...s about one fortieth inch. Springforce is scale extends far enough beyond the zero-- mark of the other scale to complete the requisite number of units, and at the same time render the two ends of the scale identical in the relative position of corresponding marks. With the plain scale a distance may belaid down or. measured reliably to the iivelhundredth or six-hundredth of aninch. With the -vernicr's attached the Adegree of accuracy is about four times as great, while the simplicity of the construction renders its cost comparatively small. But for most uses the convenience and value of this scale is lgreatly enhanced by the slide-spring S Sp, Fig. 1. This is instantly attached toer removed from the scale by means of the thumb-nuts T N, Figs. 1 and 2, and their corresponding screws, S S, made of iron or steel, and permanently fastcnedv to the scale or the nuts. For the sake of distinctness the nut in Fig..1, at the left end i ot thespring, is represented as removed, but

that .at the right end attached.

In Fig. 4-the same method of attachment is employed as in the dat scale; but. since it is ff triangular thejspring is applied to the ends of' the scale.

This :spring is usually made of brass Wire,.hardened by drawing. The lip L (seen in plan in: Fi g. r1, in sectionin Fig. 5, and represented by a dotted outline in Fig. 4) is also made of brass, `and is soldered to the wire. By means of the spring and its lip the scale is brought into contact with and becomes a sliding scale for the trigonometer or the arm of any T-square. To give it the requisite 1 springforce, the wire is so bent that the lip,

.when not drawn over the side of the arm, shall stand about one'eighth of an inch therefrom. Thus when it is drawn over, the scale is not vonly held steadily in contact with the arm, but

is slid by its thumb-nuts with great smoothness and ease, yet with sufficient friction 1o prevent anyaccidental slipping. Thisjslidespring is analogous to thatpatented with the micrometer-scale' before referred to; but the method of attachment is entirely different, as Well as the construction of the lip. It is also much more convenient-first, because, beingtightly fastened to thescale, no weight is required to keep thelip in its place; secondly,

because it'is not exposed to slip `oft'. from the i scale; and, thirdly, because thelip movin gwith more certainty and uniformity with the scale,

the latter is not liable 'to-change its position after the hand leaves the nut, as is the case with the old spring referred to.

`Since this new scale, for nearly everyv purpose. to which either is applicable, is `much more convenient than the old scale-plate of the tri gonometer, or even the micrometer-scale re -ferred to, and its cost hardly half as much,

While in practical accuracy it is superior to either, its introduction willgreatly enhance` the value of the former instrument, as well as involve an indefinite number of applications used separately by itself in every departinen of yrectilinear drafting.

' I claim as my invention- 1. Such an arrangement, application, and

graduation of the beveled edge of the scale herein set `forth as renders it a universal re liable guide to the needle-point in making a dot on the paper at the end of any required or u given `distance.

2. The arrangement and application'of theslide-spring, as set forth, to the scale herein described, by whichpit is'brought into Contact with and becomes a part of the protracting ltrigonome'ter or of a T-square. t

, JOSIAH LYMAN.

Witnesses:

WM. S. TUCKER, A. J. LYMAN. 

